1. Field of the Invention
This invention relates to a process for emulsifying an edible fat or oil, which would flavor food or improve the properties thereof, into an aqueous phase comprising soy sauce, which has been used as an excellent flavoring agent for a long time, to thereby give a stable oil-in-water type emulsion.
2. Description of the Prior Art
Recently a demand for dressings containing soy sauce as a base together with oil(s) has been increasing year by year. In conventional processes for the production of snack foods including rice crackers such as senbei, arare and okaki, soy sauce and oil(s) are separately applied to these products.
A conventional dressing of the abovementioned type comprises an aqueous phase and an oily phase which are separated from each other and mixed together just before use by shaking. Thus there are no dressings which are usually in the form of a stable oil-in-water type emulsion, except those which contain a large amount of, for example, a thickener and are thus highly viscous.
In the field of snack foods as described above, there is no emulsion which is usually stable and has such a low viscosity that it can be readily applied by, for example, spraying.
Soy sauce generally contains 15 to 17% by weight of common salt and has a low pH value, i.e., around 5, which makes it extremely difficult to emulsify an oil therein.
Although there has been frequently attempted to emulsify an edible oil in soy sauce to thereby give a stable oil-in-water type emulsion, there is no satisfactory product so far. Examples of these attempts include a process for emulsifying an oil in soy sauce to which an aqueous phase containing gelatin and natural gum(s) is added (cf. Japanese Patent Publication No. 2999/1977); and a process wherein emulsifier(s) selected from among diacetyltartaric acid monoglyceride, sucrose fatty acid esters and polyglycerol fatty acid esters are employed optionally together with a stabilizer such as modified starch (or .alpha.-starch) or sodium caseinate (cf. Japanese Patent Laid-Open No. 45854/1984).
However every emulsion prepared by these methods is inavailable in practice, because it is relatively stable when allowed to stand at a constant temperature but becomes highly unstable and liable to show the separation or aggregation of oily component(s) when subjected to vibration, stirring, temperature changes or prolonged storage, which would usually occur in actual transportation and distribution.